Microstructure and defect controlled additive manufacturing of gamma titanium aluminides for function-based control of local materials properties

上级目标是了解工艺参数、凝固和冷却条件与微观结构形成之间的基本关系，并系统地研究其对增材制造的γ-钛铝化物的变形和断裂行为的影响。通过使用EDX和EBSD探测器、X射线计算机断层扫描、高温XRD和仪器硬度映射，利用光学和扫描电子显微镜进行全面的微观结构分析，将对工艺参数和微观结构形成之间的关系有一个基本的了解。与过去的研究相比，不同的微观结构形成可以通过使用不同的能源（激光和电子束）以及在IfWW的过程中和后热处理（感应，HIP，时效，固溶退火）产生。为此，将研究基本参数（扫描速度、沉积速率、衬底温度）以及不同构建方向（垂直、水平）的影响。同时，疲劳变形和断裂行为的基本分析以及微观结构特征与疲劳性能的相关性将被允许，由于WPT的基于机制的测试方法的进一步发展，用于在室温和高温下γ-钛铝化物的疲劳行为的资源有效的表征。特别是，为了实现微观结构和性能之间的基本关系的基于模型的描述，相关矩阵中的结果的连续传输将使研究结果能够转化为工业中的增材制造γ-钛铝化物。科学主题和目标：Christoph Leyens，IfWW（第一申请人）· 研究不同工艺参数的影响，例如气氛（真空、惰性气体）对合金元素蒸发行为的影响。· 通过后续热处理生成不同的微观结构。· 开发加工、微观结构和性能之间的相关矩阵，用于制造微观结构针对局部性能量进行优化的结构。Frank Walther，WPT（第二申请人）· 表征微观结构和缺陷形成与工艺参数和后处理的关系，以及它们对准静态和疲劳变形和断裂行为的影响。· 进一步开发基于机构的测试方法，该方法基于仪器化载荷增加和恒定振幅测试，以资源有效的方式表征室温和高温下的疲劳行为。· 开发了一个物理模型，用于描述室温和高温下微观结构和缺陷特性对疲劳行为的影响。

The superior target is to understand the fundamental relationships between process parameters, solidification and cooling conditions and the microstructure formation and to systematically investigate its impact on the deformation and fracture behavior in additively manufactured gamma-titanium aluminides. Due to a comprehensive microstructure analysis with light and scanning electron microscopy by using EDX and EBSD detectors, X-ray computer tomography, high temperature XRD and instrumented hardness mappings, a fundamental understanding of the relationships between process parameters and microstructure formation will be reached. In contrast to past studies, different microstructure formations can be generated by usage of different energy sources (laser and electron beam) as well as in- and post-process heat treatments (induction, HIP, aging, solution annealing) at IfWW. For this purpose, the basic parameters (scanning speed, deposition rate, substrate temperature) as well as the influence of different building directions (vertical, horizontal) will be investigated. Simultaneously, a fundamental analysis of the fatigue deformation and fracture behavior and a correlation of the microstructure characteristics with the fatigue properties will be allowed due to a further development of the mechanism-based testing methodology of WPT for a resource-efficient characterization of the fatigue behavior of gamma-titanium aluminides at room and high temperatures. Especially, the continuously transfer of the results in correlation matrices in order to realize a model-based description of the fundamental relationships between microstructure and properties will enable a transformation of the research results to additively manufactured gamma-titanium aluminides in industry.Scientific topics and goals:Christoph Leyens, IfWW (1st applicant) • Investigation of influence of different process parameters, e.g. atmosphere (vacuum, inert gas) on the vaporization behavior of the alloying elements.• Generation of different microstructure formations due to a follow up heat treatment.• Development of correlation matrices between processing, microstructure and properties for manufacturing of structures whose microstructure is optimized for the local amount of properties.Frank Walther, WPT (2nd applicant) • Characterization of microstructure and defect formation as a function of process parameters and the post processing as well as their impact on the quasistatic and fatigue deformation and fracture behavior.• Further development of the mechanism-based testing methodology on basis of instrumented load increase and constant amplitude tests for a resource-efficient characterization of the fatigue behavior at room and high temperatures.• Development of a physically-based model for description of the impact of microstructure and defect characteristics on the fatigue behavior at room and high temperatures.